The Doctor’s Surgery
Losing weight can be bad for you
Weight loss, particularly when you’re old, can be a bad sign theodore dalrymple People are inclined to worry about their weight, most commonly because it is greater than they think it ought to be. Often these days they are right, as any walk down a street will tell you. Certainly, there is a statistical association between people’s body mass index (BMI) – their weight in kilograms divided by their height in metres squared – and their life expectancy. Though statistical association is not causation, there is a natural tendency of the human mind to suppose that it is. When the relation of BMI to life expectancy is plotted on a graph, the result is what is known as a J-shaped curve. In this case, it means that an abnormally low BMI, as well as a high one, is associated with a reduced life expectancy. Indeed, a low BMI is associated with a reduction in life expectancy as great as that associated with a high BMI. Mrs Wallis Simpson might have been mistaken when she said you cannot be too thin – at least if you want to live as long as possible. However, because a low BMI is much less common than a high one, its association with a reduced life expectancy is much less well-publicised. Unexplained involuntary loss of weight in adults (ILW – nothing is real these days until it has an acronym), though, is a serious sign. Researchers in Spain analysed nearly 800 cases of adults who presented with ILW, defined as weight loss greater than 5 per cent in the previous 12 months, without specific symptoms pointing to an obvious possible cause. This is a quite common problem with elderly people and should never be ignored. The patients’ average age was 68. They were not accepted into the study if they had symptomatic pointers to their underlying diagnosis, if they had started taking diuretics recently (thereby losing excess fluid) or if they refused follow-up treatment.
The study found that 44.5 per cent of the cases had non-malignant organic causes, most commonly of the digestive tract, for example hiatus hernia (by definition, without specific symptoms of that disease). Prescription drugs of, for example, digoxin and metformin, occult infections (particularly of the lung) and rheumatic diseases were also responsible in some cases. Next in frequency were psychiatric causes: about 29 per cent – more common in women than men. Overwhelmingly the most common psychiatric diagnosis was depression. It was probably mostly of what used to be called the endogenous type – that is to say, depression without obvious precipitating cause, or depression out of proportion to any precipitating cause. At any rate, most such cases are treatable. Severe anxiety also caused weight loss. Nearly a quarter of the patients had malignant disease, more common in men than in women, and again most commonly of the digestive tract (about
half of the cases of malignancy). The commonest cancers of the digestive tract were gastric, colonic and pancreatic, though lung cancer was more common than either colonic or pancreatic cancer. It has to be borne in mind, of course, that patterns of cancer, as of other diseases, vary in different populations: in another place, the proportions of cases might have been quite different. In about 3 per cent of cases, no cause, organic or psychiatric, was found. At 12 months, 3.6 per cent of the psychiatric cases had died, 6.4 per cent of the organic but non-malignant cases had died, and 61.1 per cent of the cancer cases had died. No controls matched for age and other factors were given, but one figure stands out nevertheless – cancer. Let us look on the bright side, however. Involuntary weight gain is for the moment a greater problem for many of us than involuntary weight loss. Let us also, perhaps, be grateful for the enjoyment that, as often as not, has given rise to it.
‘The boss really throws himself into the Christmas spirit’ The Oldie January 2022 43
